Head Rest Having Rotary Wing

ABSTRACT

The present invention relates to a headrest having a rotary wing. The headrest includes a rotary shaft installed in a seat; a wing unit having a outer casing for receiving the rotary shaft therein; a locking unit for locking the wing unit to the seat; and a return spring for returning the wing unit to an original position of the wing unit. The headrest has a simple construction for rotating the wing unit, which thus reduces the production cost of the headrest.

TECHNICAL FIELD

The present invention relates, in general, to headrests having rotarywings and, more particularly, to a headrest having a rotary wing, whichincludes a wing unit having a outer casing to receive a rotary shafttherein, a locking unit to lock the wing unit to a seat body, and areturn spring to return the wing unit to the original position of thewing unit, thus having a simple construction for rotating the wing unitand reducing the production cost of the headrests.

BACKGROUND ART

An example of conventional vehicle seats is found in Korean UtilityModel Laid-open publication No. 1998-37917.

A seatback frame is arranged in a seatback and supports the seatback. Aside headrest is eccentrically installed on the upper surface of theseatback at a position adjacent to a main headrest. At the upper end ofthe side headrest, a stay, which has an adjusting knob and extends alongan eccentric hole of the side headrest, is secured to the seatbackframe.

A gear is connected to the lower end of the stay, which is secured tothe seatback frame, such that the gear can be rotated in the samedirection when the adjusting knob is manipulated. Further, a gearedbracket is installed at a predetermined location, at which the gearedbracket engages with and is operated in conjunction with the gear bysimple manipulation of the adjusting knob, in other words, at a locationadjacent to the fixed position of the stay relative to the seatbackframe.

Further, when a passenger, who has leaned his/her head backwards againstthe headrest of a back seat while a vehicle is driven, wants to assume amore comfortable sitting and leaning posture, the passenger may rotatecounterclockwise the adjusting knob, which is installed on the eccentricshaft of the side headrest parallel to the upper surface of theseatback. In the above state, the gear, which is connected to the lowerend of the stay, engages with the gear of the seatback frame, and thusthe two gears are rotated in conjunction with each other. Therefore, theoutside end of the side headrest is slowly rotated toward the frontseat, so that the passenger, who sits in the back seat, can adjust theangle of the side headrest to a desired angle and can fix the sideheadrest at the adjusted angle prior to using the side headrest as aheadrest.

However, the headrest of the above-mentioned vehicle seat can supportthe head of a passenger when the passenger leans his/her head to oneside. Further, when two side headrests are provided on opposite sides ofa vehicle seat and a shock is applied to the vehicle seat, the two sideheadrests may not efficiently absorb the shock, and instead may injurethe head of the passenger.

Further, when the shock is applied to a passenger while the passengerleans his/her head on a side headrest, the passenger knocks his/her headagainst the side headrest, thus his/her head is easily wounded.

Further, the conventional side headrest has a complex mountingstructure, thus being heavy and increasing the production cost of theheadrests.

DISCLOSURE Technical Problem

Accordingly, the present invention has been made keeping in mind theabove problems occurring in the related art, and an object of thepresent invention is to provide a headrest having a rotary wing, whichincludes a wing unit having a outer casing to receive a rotary shafttherein, a locking unit to lock the wing unit to a seat body, and areturn spring to return the wing unit to the original position of thewing unit, thus having a simple construction for rotating the wing unitand reducing the production cost of the headrest.

Technical Solution

In order to accomplish the above object, in an aspect, the presentinvention provides a headrest having a rotary wing, comprising: a rotaryshaft installed in a seat body; a wing unit having a outer casing forreceiving the rotary shaft therein; a locking unit for locking the wingunit to the seat body; and a return spring for returning the wing unitto the original position of the wing unit.

According to the above-mentioned construction, the present invention hasa simple construction for rotating the wing unit of the headrest, thusreducing the production cost of headrests.

In another aspect, the present invention provides a headrest having arotary wing, comprising: a rotary shaft installed in a seat body; a wingunit having a outer casing for receiving the rotary shaft therein; aclutch, which engages with or disengages from the wing unit; a lockingunit for locking the clutch to the seat body; and a return spring forreturning the wing unit to the original position of the wing unit. Thus,in a state of emergency, the wing unit can be opened to prevent apassenger from being injured.

In the headrest, the clutch may comprise a responder, which detects ashock and causes the clutch to engage with or disengage from the wingunit. Thus, when an impact is applied to the seat, the wing unit can beautomatically opened to prevent a passenger from being injured.

The locking unit may comprise a protrusion; the wing unit may comprise aguide groove, which receives the protrusion therein, and a lockinggroove, which has a height higher than the guide groove and communicateswith the guide groove; and the rotary shaft may comprise a bore, whichreceives the locking unit therein, and a longitudinal guide slot, whichcommunicates with the bore and receives the protrusion therein, whereinan upper spring is provided on the locking unit, and a push member isprovided on the upper spring, and a lower spring is provided below thelocking unit. Thus, the locking unit has a simple construction, so thatthe present invention can easily release the wing unit or the clutchfrom a locked state. Further, the locking unit is installed on therotary shaft, thus realizing a headrest having a compact construction.

In the headrest, the seat comprises: a seat body; a middle body partmounted to the upper end of the body; a connection unit for connectingthe middle body part to the body, a spring provided at one side of theconnection unit; and a support unit for supporting the spring. Thepresent invention efficiently absorbs shocks which are applied to theheadrest, thus preventing a passenger from being injured.

ADVANTAGEOUS EFFECTS

The headrest having a rotary wing according to the present invention isadvantageous for the following reasons.

The headrest comprises the rotary shaft installed in the seat body, thewing unit having the outer casing for receiving the rotary shafttherein, the locking unit for locking the wing unit to the seat, and thereturn spring for returning the wing unit to its original position.Thus, the headrest has a simple construction for rotating the wing unitand thus reduces the production cost of headrests.

Further, when the headrest of the present invention is used in seats ofbuses, trains or airplanes, in which case passengers must sit in theseats for a lengthy period of time, the headrests enable the passengersto sleep comfortably.

The headrest of the present invention includes the clutch, which engageswith or disengages from the wing unit, and the locking unit for lockingthe clutch to the seat body. Thus, in a state of emergency, the wingunit can be opened to prevent a passenger from being injured.

Further, the clutch includes the responder, which detects shocks andcauses the clutch to engage with or disengage from the wing unit, sothat, when an impact is applied to the seat, the wing unit can beautomatically opened to prevent a passenger from being injured.

The locking unit includes the protrusion, while the wing unit includesthe guide groove, which receives the protrusion therein, and the lockinggroove, which is higher than the guide groove and communicates with theguide groove. Further, the rotary shaft includes the bore, whichreceives the locking unit therein, and the longitudinal guide slot,which communicates with the bore and receives the protrusion therein.Further, the upper spring is provided on the locking unit, the pushmember is provided on the upper spring, and the lower spring is providedbelow the locking unit. Due to the simple construction of the lockingunit, the present invention can easily release the wing unit or theclutch from a locked state. Further, the locking unit, which isinstalled on the rotary shaft, permits the compact construction of theheadrest.

Further, the headrest includes a spring, which is provided on one sideof the connection body, and a support unit for supporting the spring, sothat the present invention can efficiently absorb impacts applied to themiddle seat part, thus preventing a passenger from being injured.

Further, when a passenger sleeps, the wing unit may be rotated tosupport the head of the passenger. Further, the middle seat part and thewing unit may move leftwards or rightwards at the same time, thusenabling the passenger to assume a natural leaning posture, and thussleep comfortably.

The headrest includes both a nut part, which is provided in a connectionframe to be placed outside the support unit, and a bolt, which isthreaded to the nut part, so that the headrest can appropriately controlthe elasticity of springs and more efficiently absorb shocks.

Further, the headrest has both a vertical part, which is installed onthe connection body such that it is placed between the connection bodyand the support unit. In addition, a damping material is provided in thespace between the support unit and the vertical part, so that theheadrest dampens shocks and thus more stably and efficiently absorbsshocks.

DESCRIPTION OF DRAWINGS

FIG. 1 is an exploded perspective view illustrating a coupling structureof a middle seat part and a wing unit according to a second embodimentof the present invention;

FIG. 2 is a longitudinal sectional view of FIG. 1;

FIG. 3 is a cross-sectional view schematically illustrating theoperation of the coupling structures shown in FIG. 1;

FIG. 4 is a cross-sectional view schematically illustrating theoperation of coupling structures of a middle seat part and a wing unitaccording to a first embodiment of the present invention;

FIG. 5 is a longitudinal sectional view illustrating the couplingstructure shown in FIG. 4;

FIG. 6 is a cross-sectional view schematically illustrating anotheroperation of the coupling structure shown in FIG. 4;

FIG. 7 is a longitudinal sectional view illustrating a couplingstructure of a middle seat part and a wing unit according to a thirdembodiment of the present invention;

FIG. 8 is a cross-sectional view schematically illustrating theoperation of the coupling structures shown in FIG. 7;

FIG. 9 is a longitudinal sectional view illustrating a couplingstructure of a middle seat part and a wing unit according to a fourthembodiment of the present invention;

FIG. 10 is a cross-sectional view schematically illustrating theoperation of the coupling structures shown in FIG. 9;

FIG. 11 is a sectional view illustrating a connection unit according toa preferred embodiment of the present invention; and

FIG. 12 is a sectional view illustrating a connection unit according toanother embodiment of the present invention.

BEST MODE

Hereinbelow, preferred embodiments of the present invention will bedescribed in detail with reference to the accompanying drawings.

In the embodiments of the present invention, for a description ofmembers the same as those in the related art, reference is to be made tothe description of the related art, and additional description thereofis omitted.

FIG. 1 is an exploded perspective view illustrating a coupling structureof a middle seat part and a wing unit according to a second embodimentof the present invention. FIG. 2 is a longitudinal sectional view ofFIG. 1. FIG. 3 is a cross-sectional view schematically illustrating theoperation of the coupling structures shown in FIG. 1.

FIG. 4 is a cross-sectional view schematically illustrating theoperation of coupling structures of a middle seat part and a wing unitaccording to a first embodiment of the present invention. FIG. 5 is alongitudinal sectional view illustrating the coupling structure shown inFIG. 4. FIG. 6 is a cross-sectional view schematically illustratinganother operation of the coupling structure shown in FIG. 4.

FIG. 7 is a longitudinal sectional view illustrating a couplingstructure of a middle seat part and a wing unit according to a thirdembodiment of the present invention. FIG. 8 is a cross-sectional viewschematically illustrating the operation of the coupling structuresshown in FIG. 7.

FIG. 9 is a longitudinal sectional view illustrating a couplingstructure of a middle seat part and a wing unit according to a fourthembodiment of the present invention. FIG. 10 is a cross-sectional viewschematically illustrating the operation of the coupling structuresshown in FIG. 9.

FIG. 11 is a sectional view illustrating a connection unit according toa preferred embodiment of the present invention. FIG. 12 is a sectionalview illustrating a connection unit according to another embodiment ofthe present invention.

As shown in FIG. 1 through FIG. 12, the seat for vehicles according to apreferred embodiment of the present invention comprises a seat body anda headrest having a rotary wing. The headrest includes a rotary shaft230, 330, 430, 530, which is mounted in the seat body, a wing unit 260,360, 460, 560, which has a outer casing that is fitted over the rotaryshaft 230, 330, 430, 530, a locking unit 220, 320, 420, 520, which locksthe wing unit 260, 360, 460, 560 to the seat body, and a return spring250, 350, 450, 550, which returns the wing unit 260, 360, 460, 560 toits original position.

The seat body comprises the body 100 and a middle seat part 210, 310,410, 510, which is mounted to the upper end of the body 100.

The connection unit, which connects the middle seat part 210, 310, 410,510 to the body 100, comprises a connection frame 170, 670, a connectionbody 150, 650, which is installed in the connection frame 170, 670 andis connected to the middle seat part 210, 310, 410, 510, a spring 160,660, which is provided at a side of the connection body 150, 650, and asupport unit 130, 630, which supports the spring 160, 660.

The connection frame 170, 670 is provided in the upper part of the body100, and defines therein a space. The connection body 150, 650, thespring 160, 660, and the support unit 130, 630 are received in the spaceof the connection frame 170, 670, so that the connection unit of themiddle seat part 210, 310, 410, 510 is configured as a module.

The connection body 150, 650 is installed in the connection frame 170,670 and is connected to the middle seat part 210, 310, 410, 510.

The connection frame 170, 670 is provided on each side of the upper partof the connection body 150, 650 and is connected to the middle seat part210, 310, 410, 510. The connection body 150, 650 is provided with aslit, which movably receives the connection frame 170, 670 therein suchthat the connection body 150, 650 can move leftwards or rightwards.

The spring 160, 660 is provided on each side of the connection body 150,650.

The support unit 130, 630 is provided outside the spring 160, 660 andsupports the spring 160, 660.

The support unit 130, 630 comprises a front wall 134, 634, whichcontacts the spring 160, 660, a rear wall 132, 632 and a connection wall133, 633, which connects the front wall 134, 634 to the rear wall 132,632.

Further, the headrest includes a nut part 110, which is installed in theconnection frame 170, 670 and is placed outside the support unit 130,630, and a bolt 120, which is threaded to the nut part 110.

The nut part 110 is configured as a plate part, and has a through hole,which is formed through the center of the nut part 110 and is internallythreaded.

The bolt 120 comprises a bolt head part and a threaded shank part, whichis externally threaded and engages with the through hole of the nut part110.

Further, a vertical part 141, 641 is provided in the connection body150, 650 at a position between the connection body 150, 650 and thesupport unit 130, 630. A damping material 131, 631 is provided in aspace between the support unit 130, 630 and the vertical part 141, 641.

The vertical part 141, 641 is placed in the support unit 130, 630 and isconnected to the connection body 150, 650 through the connection part142, 642.

The connection part 142, 642 passes through the front wall 134, 634 ofthe support unit and moves along with the connection body 150, 650.

The damping material 131, 631, which is charged in the support unit 130,630, preferably comprises a viscous fluid, and dampens vibrationsapplied to the connection body 150, 650.

Thus, when shocks are applied to the head of a passenger, who leans onthe headrest, in which the wing unit 260, 360, 460, 560 of the middleseat part 210, 310, 410, 510 has been rotated and supports thepassenger's head, both the connection body 150, 650 and the verticalpart 141, 641 move in the impact direction, in which the wing unit 260,360, 460, 560 and the middle seat part 210, 310, 410, 510 are impacted.

In the above state, the connection body 150, 650, which is elasticallysupported by the spring 160, 660, absorbs the shock and vibrates. Thevibration of the spring 160, 660 is dampened by the damping material131, 631, so that the shock is more efficiently absorbed.

Further, the interval between the support unit 130, 630 and theconnection body 150, 650 can be adjusted by rotating the bolt 120 ineither direction, so that it is possible to adjust the elasticity of thespring 160, 660, which biases the connection body 150, 650.

The rotary shaft 230, 330, 430, 530 is installed at each side of theseat. The rotary shaft may be installed on the middle seat part 210,310, as shown in the drawings of the first embodiment and the secondembodiment, or may be installed on the body 100, as shown in thedrawings of the third embodiment and the fourth embodiment.

The rotary shaft 230, 330, 430, 530 is provided with a bore to receivethe locking unit 220, 320, 420, 520 therein, with two longitudinal guideslots 231, 232, 331, 332, 431, 531 formed in the sidewall of the rotaryshaft in vertical directions such that the guide slots receive theprotrusions 221, 321, 421, 521 and communicate with the bore.

The outer casing of the wing unit comprises a hollow part, and may bedirectly fitted over the rotary shaft 430, 530 to surround the rotaryshaft 430, 530, as shown in the drawings of the third embodiment and thefourth embodiment. Alternatively, the outer casing of the wing unit,which comprises the hollow part, may be indirectly fitted over therotary shaft 230, 330, such that a clutch is interposed between therotary shaft 230, 330 and the outer casing, as shown in the drawings ofthe first embodiment and the second embodiment.

The wing unit 260, 360, 460, 560 may be formed outside the outer casing,as shown in the drawings of the first embodiment and the secondembodiment, or may be formed on the upper part of the outer portion ofthe outer casing, as shown in the drawings of the third embodiment andthe fourth embodiment, thus supporting the head of a passenger.

The locking unit 220, 320, 420, 520 locks the wing unit 260, 360, 460,560 to the seat body, thus maintaining the position of the wing unit260, 360, 460, 560 relative to the seat body.

The locking unit 220, 320, 420, 520 may be configured as one of avariety of structures. In the embodiments, the locking unit 220, 320,420, 520 is configured as a cylindrical member, which is axiallyreceived in the bore of the rotary shaft 230, 330, 430, 530 with aprotrusion 221, 321, 421, 521 and a second protrusion 222, 322, 422, 522externally provided on the side surface of the locking unit 220, 320,420, 520.

The second protrusion 222, 322, 422, 522 is received in a secondlongitudinal guide slot 232, 332, and thus enables the locking unit 220,320, 420, 520 to move in the rotary shaft 230, 330, 430, 530 in avertical direction while maintaining horizontally.

The protrusion 221, 321, 421, 521 passes through a first longitudinalguide slot 231, 331, 431, 531 of the rotary shaft, while the secondprotrusion 222, 322, 422, 522 is inserted into the second longitudinalguide slot 232, 332, which is formed on the rotary shaft at a positiondiametrically opposite the first longitudinal guide slot 231, 331, 431,531.

The protrusion 221, 321, 421, 521 is longer than the second protrusion221, 321, 421, 521.

The outer casing of the wing unit is provided with a guide groove 246,361, which receives the protrusion 221, 321, 421, 521 therein, and alocking groove 242, 362, 446, 563, which has a height higher than theguide groove 246, 361 and communicates with the guide groove 246, 361.

The locking groove 242, 362, 446, 563 is formed at an end of the guidegroove 246, 361.

In the second embodiment and the fourth embodiment of the presentinvention, both the locking groove 362, 563 and the guide groove 361 areformed in the outer casing. Meanwhile, in the first embodiment and thethird embodiment, both the locking groove 242, 446 and the guide groove246 are formed in the clutch.

At the upper part of the locking unit 220, 320, 420, 520, an upperspring 225, 325, 425, 525 is provided. A push member 224, 324, 424, 524is installed on the top of the upper spring 225, 325, 425, 525. At thelower part of the locking unit 220, 320, 420, 520, a lower spring 228,328, 428, 528 is provided.

A support step 229, 429, 529 is provided on the inner surface of thehollow rotary shaft 230, 330, 430, 530 to stop and support the lowerspring 228, 328, 428, 528.

Further, to more efficiently transmit the pushing force of the pushmember 224, 324, 424, 524, a transmission member 226, 326, 426, 526 isplaced below the upper spring 225, 325, 425, 525.

The transmission member 226, 326, 426, 526 may be configured as a blockbody or as a frame having an I-shaped cross-section.

A ball 227, 327, 427, 527 is placed below the transmission member 226,326, 426, 526, so that, even if a user eccentrically pushes the pushmember 224, 324, 424, 524, the pushing force can be efficientlytransmitted to the locking unit 220, 320, 420, 520.

The clutch engages with or disengages from the wing unit 260, 360, 460,560. When the clutch engages with the wing unit 260, 360, 460, 560, theclutch is rotated along with the wing unit 260, 360, 460, 560 and islocked by the locking unit 220, 320, 420, 520.

When the clutch is locked as described above, the wing unit 260, 360,460, 560 is locked at the same time.

The clutch includes a responder, which detects impact and enables theclutch to engage with or disengage from the wing unit 260, 360, 460, 560in response to the detected impact.

The responder comprises a sensor, which detects impact, and an actuatingpin. In response to a signal output from the sensor, the responderactuates the actuating pin to make the clutch engage with or disengagefrom the wing unit 260, 360, 460, 560, so that the clutch may engagewith or disengage from the wing unit 260, 360, 460, 560.

The clutch comprises a first transmission unit 270, 370, 470, 570, asecond transmission unit 280, 380, 480, 580, which is received in thefirst transmission unit 270, 370, 470, 570, and a third transmissionunit 290, 390, 490, 590, which is received in the second transmissionunit 280, 380, 480, 580. The clutch further comprises a fourthtransmission unit 240, 340, 440, 540, which may be received in the thirdtransmission unit 290, 390, 490, 590 in the same manner as thatdescribed for the first embodiment and the second embodiment, or whichmay surround the first transmission unit 270, 370, 470, 570 in the samemanner as that described for the third embodiment and the fourthembodiment.

The responder according to the embodiments comprises a plurality ofblock 272, 275, 292, 295, 372, 375, 392, 395, 472, 475, 493, 495, 593,572, 575, 595, and a plurality of springs 273, 275, 292, 295, 373, 376,393, 396, 473, 476, 492, 496, 573, 574, 592, 595 to elastically supportthe block 272, 275, 292, 295, 372, 375, 392, 395, 472, 475, 493, 495,593, 572, 575, 595.

The first transmission unit 270, 370, 470, 570 is provided with a firstslot 271, 371, 471, 571, while the outer casing of the wing unit or thefourth transmission unit 240, 340, 440, 540 is provided with a firsthole at a position corresponding to the first slot 271, 371, 471, 571.

The first transmission unit 270, 370, 470, 570 is also provided with asecond slot 274, 374, 474, 576, while the second transmission unit 280,380, 480, 580 is provided with a second hole at a position correspondingto the second slot 274, 374, 474, 576.

The first slot 271, 371, 471, 571 and the second slot 274, 374, 474, 576are aligned in one straight line.

The third transmission unit 290, 390, 490, 590 is provided with a thirdslot 291, 391, 491, 591, while the outer casing of the wing unit or thefourth transmission unit 240, 340, 440, 540 is provided with a thirdhole at a position corresponding to the third slot 291, 391, 491, 591.

The third transmission unit 290, 390, 490, 590 is also provided with afourth slot 294, 394, 496, 596, while the outer casing of the wing unitor the fourth transmission unit 240, 340, 440, 540 is provided with afourth hole at a position corresponding to the fourth slot 294, 394,496, 596.

The third slot 291, 391, 491, 591 and the fourth slot 294, 394, 496, 596are aligned in one straight line, while the third slot 291, 391, 491,591 and the fourth slot 294, 394, 496, 596 are aligned in anotherstraight line, which is at an angle of 90 degrees with the straight lineof the first slot 271, 371, 471, 571 and the second slot 274, 374, 474,576.

Because the slots are formed on the transmission units at positions withthe above-mentioned angular difference, the clutch can be separated fromthe wing unit 260, 360, 460, 560 no matter which direction a shock isapplied from.

The slots and the holes, which correspond to each other, receive block272, 275, 292, 295, 372, 375, 392, 395, 472, 475, 493, 495, 593, 572,575, 595, with springs 273, 275, 292, 295, 373, 376, 393, 396, 473, 476,492, 496, 573, 574, 592, 595 seated in the slots to elastically bias theblock 272, 275, 292, 295, 372, 375, 392, 395, 472, 475, 493, 495, 593,572, 575, 595.

A protrusion 241, 341, 441, 541 protrudes downwards from the lower endof the fourth transmission unit 240, 340, 440, 540. An arcuate guidegroove 211, 311, 411, 511, which has a central angle of 90 degrees, isformed on a guide unit of the seat body, and receives the protrusion241, 341, 441, 541 therein.

In the first embodiment and the second embodiment, the fourthtransmission unit 240, 340 is provided with an upper flange 244, 344 anda lower flange 243, 343.

The upper flange 244, 344 supports the first transmission unit 270, 370,the second transmission unit 280, 380, and the third transmission unit290, 390.

The lower flange 243, 343 is provided with the protrusion 241, 341 on alower end thereof, and is furnished with teeth 245, 345 around thecircumferential surface thereof.

In the third embodiment and the fourth embodiment, a lower flange 443,543 is formed on the inner surface of the fourth transmission unit 440,540. The lower flange 443, 543 is furnished with teeth 445, 545 aroundthe circumferential surface thereof, and is provided with a protrusion441, 541 on a lower end thereof.

The return spring 250, 350, 450, 550 elastically returns the wing unit260, 360, 460, 560 to its open state.

The return spring 250, 350, 450, 550 is a torsion spring, in which thefixed end 251 of the return spring is fixed to the guide unit, while themovable end 252 of the return spring is stopped by the outer casing ofthe wing unit 260, 360, 460, 560 and is rotated along with the wingunit.

The middle seat part 210, 310, 410, 510 or the connection body 150, 650is provided with a motor to automatically rotate the wing unit 260, 360,460, 560.

The motor is provided with a gear, which engages with the teeth 245,345, 445, 545, thus rotating the fourth transmission unit 240, 340, 440,540 and rotating the wing unit 260, 360, 460, 560 at an angle of 90degrees.

When the motor is installed in the connection body 150, 650, theconnection frame 170, 670 is used as the rotary shaft 230, 330, 430, 530and both the nut part and the bolt may be removed, as shown in FIG. 12.

Further, the headrest may further comprise an unlocking unit, in which aswitch is manipulated instead of the clutch to push the transmissionmember 226, 326, 426, 526, or a push member 224, 324, 424, 524 ismanipulated to unlock the locking unit,

Thus, when an impact is applied, a passenger may directly open the wingunit 260, 360, 460, 560.

Further, the headrest may comprise an impact sensor, and thus thelocking unit may be automatically unlocked even if a passenger does notmanipulate the switch.

Hereinbelow, the operation of the embodiments of the present inventionwill be described.

As shown in FIG. 5, in a normal state (a) of the first embodiment, thewing unit 260 is in an opened state. When a passenger wants to use thewing unit 260 for sleeping, the passenger rotates the wing unit 260 atan angle of 90 degrees.

When the wing unit 260 is rotated as described above, the clutch, whichis coupled to the wing unit 260, is rotated along with the wing unit260. Thus, the protrusion 221 is inserted into the guide groove 246 ofthe fourth transmission unit 240 and is rotated along the guide groove246. When the protrusion 221 has been rotated at an angle of 90 degrees,the protrusion 221, which is biased upwards by the lower spring 228, isinserted into the locking groove 242, so that the wing unit 260 islocked to the clutch.

When an external shock is applied to the wing unit 260 in the abovestate, the block 272, 275 are retracted inwards from the first slot 271and the second slot 274 due to the shock.

When the block 272, 275 are retracted during the impact state (c), asdescribed above, the block 272, 275, which have functioned as pins forlocking the wing unit 260 to the clutch, are removed from the outercasing, so that the wing unit 260 is separated from the clutch.

When an external shock is applied to the headrest in the oppositedirection, the block 272, 275 are retracted inwards from the third slot291 and the fourth slot 294, so that the wing unit 260 is separated fromthe clutch.

As described above, the clutch is fabricated with a plurality oftransmission units, which are coupled to each other using the block 272,275 and the springs 273, 276, so that, regardless of the direction fromwhich a shock is applied to the headrest, the wing unit 260 can bereliably opened.

Further, the protrusion 221 is locked to the locking groove 242 of thefourth transmission unit 240, so that, even if a passenger does not pushthe push member 224, the wing unit 260 can be returned to its open stateby the return spring 250.

Meanwhile, when a passenger pushes the push member 224 to open the wingunit 260 and thus change the state of the wing unit 260 from the usagestate (b) to the normal state (a), the pushing force is transmitted tothe locking unit 220 through the transmission member 226 and the ball227. Due to the transmitted pushing force, the protrusion 221 movesdownwards along the first longitudinal guide slot 231.

When the push member 224 is released from the pushing force, the pushmember 224 is returned to its original position by the upper spring 225.

Thus, the locked state is released and the wing unit 260 is returned toits open state by the return spring 250.

However, as shown in FIG. 6, the initial state of the wing unit 260 maybe set to a position at which the wing unit 260 has been rotated at anangle of 90 degrees.

In a normal state, the wing unit 260, which has the initial state at theposition rotated at the angle of 90 degrees and is used in a back seat,is oriented backwards in the body 100. When a passenger wants to changethe state of the wing unit 260 to the usage state (b) to support his/herhead, the wing unit 260 is rotated forwards at an angle of 90 degrees.When a shock is applied to the headrest, the wing unit 260 is opened.

As shown in FIG. 3, in a normal state, the wing unit 360 of the secondembodiment is in a 180 degree closed position. In the above state, theprotrusion 321 is locked to the locking groove 362 of the outer casing,and the wing unit 360 is maintained in the 180 degree closed position.

When a passenger, who wants to use the wing unit 360, pushes the pushmember 324, the protrusion 321 moves downwards and is released from thelocking groove 362. Thereafter, the protrusion 321 is moved along theguide groove 361 of the outer casing by the restoring force of thereturn spring 350.

In the embodiments, the central angle of the guide groove 361 ispreferably set at an angle of 180 degrees. Further, the central angle ofthe second longitudinal guide slot 342, which is formed on the fourthtransmission unit 340 such that the second longitudinal guide slot 342becomes level with the first longitudinal guide slot 331 of the rotaryshaft 330, is preferably set to an angle of 180 degrees. Thus, the firstlongitudinal guide slot 331 and the second longitudinal guide slot 342do not disturb the vertical movement of the protrusion 321.

The protrusion 341 of the fourth transmission unit 340 is rotated alongthe guide groove 311 of the guide unit, which has a central angle of 90degrees.

When the wing unit 360 has been rotated at an angle of 90 degrees, theprotrusion 341 of the clutch is stopped by the guide groove 311, so thatboth the clutch and the wing unit 360 are maintained in the 90 degreerotated state, thus being put in the locked state, which is the usagestate (b).

Further, when an external shock is applied to the wing unit 360, thewing unit 360 is put in the impact state (c). In the above state, theblock 372, 375 are retracted in the same manner as that described forthe first embodiment, and the block 372, 375, which have functioned aspins for connecting the wing unit 360 to the clutch, are retracted fromthe outer casing, so that the wing unit 360 is separated from theclutch.

In the above state, the guide groove 361 of the outer casing, so thatthe wing unit 360 is opened.

When the wing unit 360, which is closed at an angle of 180 degrees, isused in a front seat of a vehicle, the wing unit 360 in a nonuse staterealizes a compact seat and thus does not obstruct a driver's field ofvision.

As shown in FIG. 8, the wing unit 460 of the third embodiment in anormal state (a) is maintained in an opened state. When the wing unit460 is put in a usage state (b), the wing unit 460 is rotated at anangle of 90 degrees and is maintained at this rotated position.

When a passenger rotates the wing unit 460 in the normal state (a) byhand, the clutch, which is coupled to the wing unit 460, is rotated, sothat the protrusion 421 is inserted into and is rotated along the guidegroove of the fourth transmission unit 440. When the protrusion 421 hasbeen rotated along the guide groove of the fourth transmission unit 440at an angle of 90 degrees, the protrusion 421 is stopped by the lockinggroove 446, so that both the clutch and the wing unit 460 are put in thelocked state, that is, the usage state (b).

To prevent the outer casing of the wing unit from interfering with therotation of the protrusion 421, the outer casing is provided with alongitudinal slot 463, which is leveled with the longitudinal guide slot431 of the rotary shaft 430 and has a central angle of 90 degrees.

When an external shock is applied to the wing unit 460, the wing unit460 is put in an impact state (c). In the above state, the block 472,475 of the first and second slots 471 and 474 are retracted inwards bythe shock.

When the block 472, 475 are retracted inwards as described above, theblock 472, 475, which have functioned as pins for connecting the wingunit 460 to the clutch, are retracted from the outer casing, so that thewing unit 460 is separated from the clutch.

However, when an external shock is applied to the headrest in theopposite direction, the block 493, 495 of the third slot 491, 591 areretracted inwards due to the shock, so that the wing unit 460 isseparated from the clutch.

The protrusion 421 is locked to the locking groove 446 of the fourthtransmission unit 440, while the longitudinal slot 463 is formed in theouter casing to enable the free rotation of the protrusion 421. Thus,even if a passenger does not push the push member 424, the wing unit 460can be returned to its opened state by the return spring 450.

Meanwhile, when a passenger pushes the push member 424 to open the wingunit 460 and thus change the state of the wing unit 460 from the usagestate (b) to the normal state (a), the pushing force is transmitted tothe locking unit 420 through both the transmission member 426 and theball 427. Due to the transmitted force, the protrusion 421 movesdownwards along the longitudinal guide slot 431, 463.

Thus, the locked state is released and the wing unit 460 is returned toits open state by the return spring 450.

As shown in FIG. 10, the wing unit 560 of the fourth embodiment in anormal state (a) is maintained in a 180 degree closed state. Further,the protrusion 521 is locked to the locking groove 563 of the outercasing, so that the wing unit 560 is maintained in the 180 degree closedstate.

When a passenger pushes the push member 524 to use the wing unit 560,the protrusion 521 moves downwards and thus is removed from the lockinggroove 563. The protrusion 521 is moved along the guide groove of theouter casing by the restoring force of the return spring 550.

In the above state, the central angle of the guide groove is preferablyset to 180 degrees, so that the guide groove does not interfere with themovement of the protrusion 521.

The protrusion 541 of the fourth transmission unit 540 is rotated alongthe guide groove 511 of the guide unit, which has a central angle of 90degrees.

When the wing unit 560 has been rotated at the angle of 90 degrees, theprotrusion 541 of the clutch is stopped by the end of the guide groove511, so that both the wing unit 560 and the clutch are maintained at a90 degree rotated state, thus being put in a locked state.

Further, when an external impact is applied to the wing unit 560, theblock 572, 575 are retracted in the same manner as that described forthe first embodiment. In the above state, the block 572, 575, which havefunctioned as pins for connecting the wing unit 560 to the clutch, areremoved from the outer casing. Thus, the wing unit 560 is separated fromthe clutch.

In the above state, the protrusion 521 moves along the guide groove ofthe outer casing, which has a central angle of 180 degrees, so that thewing unit 560 is opened.

Although preferred embodiments of the present invention have beendescribed for illustrative purposes, those skilled in the art willappreciate that various modifications, additions and substitutions arepossible, without departing from the scope and spirit of the inventionas disclosed in the accompanying claims.

1. A headrest having a rotary wing, comprising: a rotary shaft installedin a seat body; a wing unit having a outer casing for receiving therotary shaft therein; a locking unit for locking the wing unit to theseat body; and a return spring for returning the wing unit to anoriginal position of the wing unit.
 2. A headrest having a rotary wing,comprising: a rotary shaft installed in a seat body; a wing unit havinga outer casing for receiving the rotary shaft therein; a clutch, whichengages with or disengages from the wing unit, a locking unit forlocking the clutch to the seat body; and a return spring for returningthe wing unit to an original position of the wing unit.
 3. The headresthaving the rotary wing according to claim 2, wherein the clutchcomprises a responder, which detects shocks and causes the clutch toengage with or disengage from the wing unit.
 4. The headrest having therotary wing according to claim 1, wherein the locking unit comprises aprotrusion; the wing unit comprises a guide groove, which receives theprotrusion therein, and a locking groove, which has a height higher thanthe guide groove and communicates with the guide groove; and the rotaryshaft comprises a bore, which receives the locking unit therein, and alongitudinal guide slot, which communicates with the bore and receivesthe protrusion therein, wherein an upper spring is provided on thelocking unit, and a push member is provided on the upper spring, and alower spring is provided below the locking unit.
 5. The headrest havingthe rotary wing according to claim 1, wherein the seat body comprises: abody; a middle seat part mounted to an upper end of the body; and aconnection unit for connecting the middle seat part to the body, whereinthe connection unit comprises: a connection frame; a connection bodyinstalled on the connection frame and connected to the middle seat part,a spring provided on a side of the connection body; and a support unitfor supporting the spring.
 6. The headrest having the rotary wingaccording to claim 2, wherein the seat body comprises: a body; a middleseat part mounted to an upper end of the body; and a connection unit forconnecting the middle seat part to the body, wherein the connection unitcomprises: a connection frame; a connection body installed on theconnection frame and connected to the middle seat part, a springprovided on a side of the connection body; and a support unit forsupporting the spring.